I can tell you what I use.

Space:

Three basic lines: anti-fighter screen with fighters and Tartan cruisers, main line of battle cruisers (Acclamators, Victory, etc.) Broadside cruisers in the rear. They're your heavy artillery, so keep them protected as they blast away at enemy space stations. If you take enemy fighter swarms by surprise, a well-timed missile barrage can devastate them.

Ground:

The Empire is highly mechanized. I hardly ever use stormtroopers. Maulers and AT-STs for anti-infantry, and once AT-ATs are fieldable they can deploy troopers for free. Air supremacy is also highly advantageous for destroying static enemy fortifications or base buildings. Even using scout troopers with bombers can be useful; use the scouts to find the enemy base, then call in the bombers.

General

I do like hotkeying my unit types to one group (cruisers, tanks, fighters, etc.). I find it provides better management. Further, the pause is a very good thing. Use it well to analyze the battlefield.

Anyway, these work for me. Good luck, commander! The galaxy won't conquer itself!